This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The purpose of this study is to provide a registry of baseline and outcome data for very low birth weight infants (1501 grams), based on data collected in a uniform manner from neonatal intensive care units (NICUs) at institutions participating in the NICHD Neonatal Research Network. The data base will be used to characterize the infants admitted to the participating NICUs, to examine the relationships between certain entry characteristics and outcome, to measure trends in incidence of various disease entities, and to provide the basis for hypothesis formulation for future multi-center studies. Baseline and outcome data will be collected on all liveborn infants with birth weight from 401 to 1500 grams who are admitted to the participating NICUs within 14 days of birth or infants with a heart rate at birth who died in the delivery room. These data will be obtained by review of the mother's and baby's charts. This is a chart review study only, no procedures or interventions are involved.